In Defense of Case Series: Hip SCFE, Shoulder Instability and Arthritis, Double-Bundle ACL Cyclops Lesions, and Elbow OCD

Abstract

We have been critical of case series, or Level IV evidence. Case series are low in the hierarchy of levels of evidence, and studies of higher levels of evidence are best able to answer clinical questions.1Lubowitz J.H. Poehling G.G. Clinically relevant articles of high levels of evidence are required to change surgical practice.Arthroscopy. 2007; 23: 803Abstract Full Text Full Text PDF PubMed Scopus (21) Google Scholar We have recently warned potential authors: “Two-year comparative clinical outcome studies are preferred. Authors may please also observe that comparative denotes inclusion of clinical controls, and Level IV evidence cases series are no longer encouraged.”2Lubowitz J.H. Poehling G.G. Mature and with an eye to the future.Arthroscopy. 2010; 26: 721-722Abstract Full Text Full Text PDF PubMed Scopus (8) Google Scholar Yet, we have also acknowledged that case series are the most common in the surgical literature, including in Arthroscopy.3Lubowitz J.H. Poehling G.G. Comparative effectiveness research: We must lead (so as not to be misled).Arthroscopy. 2009; 25: 455-456Abstract Full Text Full Text PDF PubMed Scopus (21) Google Scholar The trend continues. In this issue we publish 5 case series. As editors, our initial response, before we even read the articles was, “Too bad the level of evidence is not higher. The authors should have included a comparative or control group.” Today, however, we reconsider our position. To be clear, we still strongly prefer comparative studies of higher levels of evidence. However, although we adamantly deny that we may be mellowing with age, we admit that a case series does play an important role. The case series in this issue have particular merit and are worthy of note. To start, we were impressed and amazed by “Trapezoidal Bony Correction of the Femoral Neck in the Treatment of Severe Acute-on-Chronic Slipped Capital Femoral Epiphysis” by Akkari et al.4Akkari M. Santili C. Braga S.R. Polesello G.C. Trapezoidal bony correction of the femoral neck in the treatment of severe acute-on-chronic slipped capital femoral epiphysis.Arthroscopy. 2010; 26: 1489-1495Abstract Full Text Full Text PDF PubMed Scopus (13) Google Scholar from São Paolo, Brazil. In this example, the case series is so much more powerful than a simple technical note. Instead of writing, “Look what we can do!” which is the message of a technical note, the authors are able to exclaim, “Look at the 2-year outcomes!” The authors find clinical and radiographic improvement and also disclose that 1 of their 5 patients had a late complication. A technical note would have shown neither of these important findings. We commend the authors on their originality, technical facility, and carefully reported follow-up. We are similarly pleased by the article, “Arthroscopic Bankart-Bristow-Latarjet Procedure: The Development and Early Results of a Safe and Reproducible Technique” by Boileau et al.5Boileau P. Mercier N. Roussanne Y. Thélu C.É. Old J. Arthroscopic Bankart-Bristow-Latarjet procedure: The development and early results of a safe and reproducible technique.Arthroscopy. 2010; 26: 1434-1450Abstract Full Text Full Text PDF PubMed Scopus (174) Google Scholar of Nice, France. The authors build on previously published technical notes describing an arthroscopic Bristow-Latarjet procedure6Boileau P. Bicknell R.T. El Fegoun A.B. Chuinard C. Arthroscopic Bristow procedure for anterior instability in shoulders with a stretched or deficient capsule: The “belt-and-suspenders” operative technique and preliminary results.Arthroscopy. 2007; 23: 593-601Abstract Full Text Full Text PDF PubMed Scopus (107) Google Scholar, 7Lafosse L. Lejeune E. Bouchard A. Kakuda C. Gobezie R. Kochhar T. The arthroscopic Latarjet procedure for the treatment of anterior shoulder instability.Arthroscopy. 2007; 23: 1242.e1-1242.e5www.arthroscopyjournal.orgAbstract Full Text Full Text PDF PubMed Scopus (331) Google Scholar by combining a Bristow-Latarjet transfer procedure with a Bankart repair. However, instead of merely describing their triple-blocking bumper, bone, and belt effect in a technical note, where readers would have only a hypothetical idea as to the risks, benefits, or outcomes of a new technique, Dr. Boileau submitted a case series. We therefore learn that the technique required conversion from arthroscopic to open surgery in 12% of cases, and these cases occurred early in the authors' learning curve. We also are assured by the outstanding clinical outcomes and cautioned by reported complications. Again, a technical note would have shown none of these important findings. This procedure is described as complex with a steep learning curve, requiring expertise and technical skill, and also as potentially dangerous because of the proximity of the brachial plexus and axillary vessels. On the basis of their experience, the authors “advise surgeons to gradually transition from open, to mini-open, and finally to all-arthroscopic, as is commonly done with rotator cuff repair.”5Boileau P. Mercier N. Roussanne Y. Thélu C.É. Old J. Arthroscopic Bankart-Bristow-Latarjet procedure: The development and early results of a safe and reproducible technique.Arthroscopy. 2010; 26: 1434-1450Abstract Full Text Full Text PDF PubMed Scopus (174) Google Scholar It is our estimation that this beautifully illustrated case series is of significant value to advanced shoulder arthroscopic surgeons. Schoch and Wolf8Schoch B. Wolf B.R. Osteochondritis dissecans of the capitellum: Minimum 1-year follow-up after arthroscopic debridement.Arthroscopy. 2010; 26: 1469-1473Abstract Full Text Full Text PDF PubMed Scopus (47) Google Scholar from the University of Iowa describe “Osteochondritis Dissecans of the Capitellum: Minimum 1-Year Follow-Up After Arthroscopic Debridement.” The mean follow-up is 3.6 years. This retrospective case series of 13 patients shows that the procedure offers patients improved function and symptomatic relief but is not reliable for unrestricted return to high-level sport. This case series has many limitations, not least of which is the absence of a control group; however, the pathology is rare, and treatment options may be limited, which emphasizes the challenges of performing outcomes research of higher levels of evidence. We clearly restate that we prefer comparative studies, but we respectfully acknowledge that we have gained valuable information from this series reported by Schoch and Wolf. New procedures, such as double-bundle reconstruction of the anterior cruciate ligament,9Lubowitz J.H. Poehling G.G. Double-bundle anterior cruciate ligament reconstruction: As simple as ABC, or putting the cart before the horse?.Arthroscopy. 2008; 24: 1089-1091Abstract Full Text Full Text PDF PubMed Scopus (13) Google Scholar may result in new complications. A case report could be an important first step in urgently notifying other readers about the risks of a new procedure, but a series of cases provide higher levels of evidence and additional information such as frequency and characterization of pathology, as well as results of the treatment of the complication. In the case series “Clinical and Operative Characteristics of Cyclops Syndrome After Double-Bundle Anterior Cruciate Ligament Reconstruction” by Sonnery-Cottet et al.,10Sonnery-Cottet B. Lavoie F. Ogassawara R. et al.Clinical and operative characteristics of cyclops syndrome after double-bundle anterior cruciate ligament reconstruction.Arthroscopy. 2010; 26: 1483-1488Abstract Full Text Full Text PDF PubMed Scopus (41) Google Scholar we learn the clinical and operative characteristics of the cyclops lesion, the incidence and outcomes of treatment, and the complications of treatment. Although future research could compare other options for treating the complication of cyclops lesion after ACL reconstruction (and would therefore achieve higher levels of evidence), we praise the authors for disclosing the complication and educating us on the characteristics and outcomes. Finally, we admire the case series “Retrospective Analysis of Arthroscopic Management of Glenohumeral Degenerative Disease” by Van Thiel et al.11Van Thiel G.S. Sheehan S. Frank R.M. et al.Retrospective analysis of arthroscopic management of glenohumeral degenerative disease.Arthroscopy. 2010; 26: 1451-1455Abstract Full Text Full Text PDF PubMed Scopus (85) Google Scholar from Chicago. Patients were treated for glenohumeral arthritis by the technique of arthroscopic debridement. As above, we wish the authors had included a control group so that we could compare these results with other treatments or no treatment. However, focusing on the positive, we have learned that case series have value, and this article is no exception. In their clever analysis, the authors identified 2 groups: patients in whom the index procedure failed and who progressed to shoulder arthroplasty surgery, and patients who had improvements in pain and function as a result of arthroscopic debridement.11Van Thiel G.S. Sheehan S. Frank R.M. et al.Retrospective analysis of arthroscopic management of glenohumeral degenerative disease.Arthroscopy. 2010; 26: 1451-1455Abstract Full Text Full Text PDF PubMed Scopus (85) Google Scholar Next, the authors identified and described the significant risk factors for failure. This information is of immense value to clinicians and their patients with shoulder arthritis, and may specifically advise future patient management recommendations and decisions regarding when, or how, to treat. Case series are limited by the absence of a comparison group or control group. Absent a control or comparison, how do we know that the treatment described is better than other treatments or no treatment? We prefer that when investigators perform new techniques, they compare their results by also performing their previously preferred technique so that the results of the new technique can be compared with an established gold standard. This results in research of higher levels of evidence, which is most valuable in answering clinical questions. However, sometimes a pathologic condition may be quite rare and, in such cases, performing research of higher levels of evidence may be difficult. In other instances, it might be unethical to relegate patients to a control group when no treatment or open (as opposed to arthroscopic) treatment is considered inferior in the mind of a potential investigator. This raises consideration of the ethical principle of equipoise, where clinical equipoise requires that there must be genuine uncertainty as to which treatment is of greater benefit when assigning patients to different treatment arms of a clinical trial.12WikipediaClinical equipoise.http://en.wikipedia.org/wiki/Clinical_equipoiseGoogle Scholar Absent equipoise, investigators should not perform comparative-effectiveness research; in some cases, Level IV evidence (case series) may actually be preferred. Finally, in many instances, publication of a case series could be a step up the research ladder, where previous technical notes or case reports have suggested the benefits of assessing outcomes in a series of patients over time, and where publication of such a series may then suggest the future benefits of assessing outcomes in comparison to other treatments.13Lubowitz J.H. Understanding evidence-based arthroscopy.Arthroscopy. 2004; 20: 1-3Abstract Full Text Full Text PDF PubMed Scopus (17) Google Scholar In other words, case series have a place in the hierarchy of levels of evidence, and well-performed case series, as represented in this issue, may help us better treat patients today and help us perform better research tomorrow.